If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Comment

You can try installing powertop to check what's sucking you CPU time, but you'll want to read something about it to know what to look for. The graphics card is the other big power drain, so you may want to share what hardware you have and what drivers you use.

Comment

And what's the best distribution for laptops? (with best power management etc.)

I don't know, I'd say they're all the same. The stuff power consumption depends on should be in the kernel and drivers, so any recent version of whatever distribution will behave similarly. What may change are certain default options such as perhaps integrating laptop-mode tools or screen blanking time; I don't quite know.

I'd just choose a distribution based on how you like its 'feeling' and then ask specific question regarding whatever power management problems you find. You may also want to look into distributions specifically targeted at netbooks (Moblin, Ubuntu Netbook edition and so on), probably there's more care taken on the power management issue on those...

What graphics card you have? Do you know what driver you are using?

Comment

I don't know, I'd say they're all the same. The stuff power consumption depends on should be in the kernel and drivers, so any recent version of whatever distribution will behave similarly. What may change are certain default options such as perhaps integrating laptop-mode tools or screen blanking time; I don't quite know.

I'd just choose a distribution based on how you like its 'feeling' and then ask specific question regarding whatever power management problems you find. You may also want to look into distributions specifically targeted at netbooks (Moblin, Ubuntu Netbook edition and so on), probably there's more care taken on the power management issue on those...

What graphics card you have? Do you know what driver you are using?

Mobillity Radeon HD 530v, open source drivers, but I can have amd drivers too.

Comment

Mobillity Radeon HD 530v, open source drivers, but I can have amd drivers too.

OK, I think that your card belongs to the r7XX generation. If that's right, there should be some power options available to you, but alas, only with relatively new kernels (this would explain why you don't get much battery life at the moment). It appears that Ubuntu 10.04 ships with kernel 2.6.32, whereas the power management code for the radeon driver requires 2.6.35. Your options are: a) look for a more up-to-date kernel version from backports repositories (I don't even know if they are available, but it's possible); b) compile your own kernel (you probably don't want to go through this if you were happy to change distribution); c) install the newest Ubuntu release, currently in beta status, which will be officially out in 30 days; d) install any other distribution shipping a kernel as recent as 2.6.35. Note that the first two options would not suffice, since you'd also need to install recent versions of the driver itself, from backports repositories or compiled from source. Personally, I'd go for option (c) since you are already familiar with Ubuntu.

Anyway, once you somehow manage to have the required kernel and driver versions, the power state of the card can be consulted through its sysfs interface:

Code:

cd /sys/class/drm/card0/device/
cat power_method

You will have two options at this point, "profile" and "dynpm". The latter is the coolest and most aggressive of the two, aiming to dynamically change the power state of your card depending on the load, but some people noticed artifacts under normal desktop operation. Try it out and see how it feels. The "profile" method enables you to set a power state permanently. Depending on I don't know what, the possible states include:

"default" uses the default clocks and does not change the power state. This is the default behavior.
"auto" selects between "mid" and "high" power states based on the whether the system is on battery power or not. The "low" power state are selected when the monitors are in the dpms off state.
"low" forces the gpu to be in the low power state all the time. Note that "low" can cause display problems on some laptops; this is why auto only uses "low" when displays are off.
"mid" forces the gpu to be in the "mid" power state all the time. The "low" power state is selected when the monitors are in the dpms off state.
"high" forces the gpu to be in the "high" power state all the time. The "low" power state is selected when the monitors are in the dpms off state.

I use the "low" profile at all times, but I own a different card. Again, try it out.

So finally, to set the power method you have to choose between "profile" and "dynpm", like this (as root user):

Code:

echo profile > power_method
or
echo dynpm > power_method

The "dynpm" method doesn't take any options; while "profile" needs one of the values mentioned above, so to set the lowest power state you'd do:

Code:

echo low > power_profile

For completeness, you also have the choice of going with the proprietary driver, which has its own set of advantages and some disadvantages. If you do so, there might be a graphical interface to control the power options (I don't really know); if not, your friendly commands are:

Code:

aticonfig --list-powerstates
aticonfig --set-powerstate=X

The first one should spit the power states available to your card. The second one sets the power state X from the previous list.

Good luck.

Comment

OK, I think that your card belongs to the r7XX generation. If that's right, there should be some power options available to you, but alas, only with relatively new kernels (this would explain why you don't get much battery life at the moment). It appears that Ubuntu 10.04 ships with kernel 2.6.32, whereas the power management code for the radeon driver requires 2.6.35. Your options are: a) look for a more up-to-date kernel version from backports repositories (I don't even know if they are available, but it's possible); b) compile your own kernel (you probably don't want to go through this if you were happy to change distribution); c) install the newest Ubuntu release, currently in beta status, which will be officially out in 30 days; d) install any other distribution shipping a kernel as recent as 2.6.35. Note that the first two options would not suffice, since you'd also need to install recent versions of the driver itself, from backports repositories or compiled from source. Personally, I'd go for option (c) since you are already familiar with Ubuntu.

Anyway, once you somehow manage to have the required kernel and driver versions, the power state of the card can be consulted through its sysfs interface:

Code:

cd /sys/class/drm/card0/device/
cat power_method

You will have two options at this point, "profile" and "dynpm". The latter is the coolest and most aggressive of the two, aiming to dynamically change the power state of your card depending on the load, but some people noticed artifacts under normal desktop operation. Try it out and see how it feels. The "profile" method enables you to set a power state permanently. Depending on I don't know what, the possible states include:

I use the "low" profile at all times, but I own a different card. Again, try it out.

So finally, to set the power method you have to choose between "profile" and "dynpm", like this (as root user):

Code:

echo profile > power_method
or
echo dynpm > power_method

The "dynpm" method doesn't take any options; while "profile" needs one of the values mentioned above, so to set the lowest power state you'd do:

Code:

echo low > power_profile

For completeness, you also have the choice of going with the proprietary driver, which has its own set of advantages and some disadvantages. If you do so, there might be a graphical interface to control the power options (I don't really know); if not, your friendly commands are:

Code:

aticonfig --list-powerstates
aticonfig --set-powerstate=X

The first one should spit the power states available to your card. The second one sets the power state X from the previous list.

Good luck.

Thanks for your detailed answer, I'll wait for Ubuntu 10.10 and then I'll try to do something with that.